This invention relates to an apparatus for filtering a well bore fluid. More particularly, but not by way of limitation, this invention relates to an apparatus positioned in a tubular member in order to filter a well bore fluid. The invention also describes the method of filtering the well bore fluid with the apparatus.
The use of drilling fluids for the drilling of oil and gas wells is well known. The drilling fluid serves many purposes, including suppression of reservoir pressure, lubrication of the drill pipe, and cooling of the bottom hole assemblies, etc. The bottom hole assemblies may contain individual components such as bits, stabilizers, measurement while drilling tools, etc. Many times, the bottom hole assemblies contain electronic sections such as microprocessors that are used to collect and/or transmit data collected by sensors placed in the bottom hole assemblies.
Drilling fluids may contain many different types of components such as mud, chemicals, drill cuttings, metal shavings, etc. The particle size of these various components vary from microns to inches. Additionally, rig crews may inadvertently drop tools, glooves, rags or other unwanted materials into the well bore. The unwanted and/or undesirable solids, hereinafter. referred to as debris, is highly harmful. For instance, the debris can cause failures in the electrical components of the bottom hole assemblies. Therefore, operators find it desirable to filter the drilling fluid of the debris.
Many methods of filtering well bore fluid exists. One present method includes placing a filter in the tubular members while the tubular members are being run into the well bore. The prior art devices presently available utilize a cylindrical screen that have an external fishing neck. However, these types of devices have many disadvantages. For instance, the openings contained in the top end have a limited flow through area. Additionally, the external fishing neck has an inherent weak point at the stem making it possible for the stem to break off while in the tubular members, which would be highly undesirable and/or dangerous, as those of ordinary skill in the art will recognize.
Therefore, there is a need for an apparatus for filtering a drilling fluid. There is also a need for a filtering device that can be retrieved from a well bore safely and quickly. Further, there is a need for a filtering device that efficiently filters the drilling fluid while still allowing maximum flow through capabilities. These needs, as well as many others, will be met by the invention herein disclosed.
A system for filtering a drilling fluid in a tubular string is disclosed. A first tubular member having a box end and a second tubular member having a pin end is provided. The box end is threadedly connected to the pin end, and wherein the connection forms a cavity. The connected tubular members have an internal bore therethrough.
The system comprises a cylindrical flange member having a first passage and a second passage, and wherein the cylindrical flange member is fitted into the cavity. The system further comprises a cylindrical sleeve having an internal bore, and wherein the internal bore contains a fishing neck. The cylindrical sleeve contains a first opened end and a second opened end. An attachment member that attaches the cylindrical flange member to the first opened end of the cylindrical sleeve is included.
The system further includes a screen member extending from the second opened end of the cylindrical sleeve, with the screen member having a plurality of openings. A pulling tool for engagement with the fishing neck is also included, with the pulling tool comprising: a mandrel with a first end and a second end; a plurality of dog members disposed about the mandrel; a spring urging the dog members into engagement with the mandrel""s first end; and wherein the dog members have a shoulder that cooperates and engages with the fishing neck. The pulling tool may further comprise a shear pin attaching the dog members to the mandrel, and wherein the mandrel contains a slot, and wherein the shear pin is disposed within the slot so that the dog members can move axially relative to the mandrel.
In one embodiment, the first passage and the second passage are disposed off-centered so that the first passage includes a first bore hole and a second bore hole, and the second passage includes a third bore hole and a fourth bore hole and wherein the attachment member comprises a first shear pin through said first and second bore hole and a second shear pin through said third and fourth bore hole. The cylindrical flange member may contain a first sealing surface that cooperates with the cavity in order to seal the cylindrical flange member relative to the internal bore.
In one embodiment, the screen member is a cylindrical ribbed body. In another embodiment, the screen member is a cylindrical body having openings therein.
A method of cleaning a drilling fluid of debris within a plurality of tubular members is also disclosed. The tubular members are threadedly connected, and the plurality of tubular members include a first tubular member having a box end and a second tubular member having a pin end. The box is threadedly connected to the pin, and wherein the box and pin cooperate to form a cavity. The method comprises placing a screen apparatus within the first tubular member. The screen apparatus comprises: a cylindrical flange member, with the cylindrical flange member having a first and second passage, and wherein the cylindrical flange member is fitted into the cavity; a cylindrical sleeve having an internal bore that contains a fishing neck; and a screen member attached to the cylindrical sleeve.
The method further includes seating the cylindrical flange member within the cavity, and passing the drilling fluid through the internal bore. Next, the drilling fluid is flown through the screen member and debris is collected within the screen member. The method includes providing a pulling tool. The pulling tool contains: a mandrel with a first end and a second end; a plurality of dog members disposed about the mandrel; a spring urging the dog members into engagement with the mandrel""s first end; and wherein the dog members have a shoulder that cooperates and engages with the fishing neck of the cylindrical sleeve.
The method further includes lowering the pulling tool into the tubular member and contacting the dog members with the cylindrical sleeve. The dog members are allowed to contract about the mandrel. The protuberance is allowed to pass the fishing neck, and the pulling tool is lowered. The dog members then are allowed to engage the shoulder of the fishing neck. Thereafter, the pulling tool may be raised.
The method further comprises shearing the first and second shear pin and releasing the cylindrical sleeve from the cylindrical flange. Next, the pulling tool is pulled with the attached screen member from the tubular member. The tubular members are pulled from the well bore, and the tubular members are threadedly disconnected. The cylindrical flange is retrieved.
Also disclosed is an apparatus for filtering a drilling fluid. The apparatus comprises a flange member having a first and second passage. A cylindrical sleeve having an internal bore is included, with the internal bore containing a fishing neck. The apparatus further includes means for attaching the flange member to the sleeve and a screen member attached at a second opened end of the sleeve. In one embodiment, the first passage and the second passage are offset from center so that four bore holes are formed. In the preferred embodiment, the attaching means includes a first shear pin through the first and second bore holes and cooperating with a groove on outer diameter of the cylindrical sleeve and a second shear pin through the third and fourth bore holes and cooperating with the groove on the outer diameter of the cylindrical sleeve. In one embodiment, the flange member has a first seating surface that cooperates with a cavity that is formed from the pin and box connection.
The apparatus may further include a pulling tool. The pulling tool includes a mandrel, a plurality of dog members disposed about the mandrel, and a spring urging the dog members into engagement with the mandrel""s first end. The dog members will have a shoulder that cooperates and engages with the fishing neck of the sleeve.
An advantage of the present invention includes the filtering of the drilling fluid so that down hole tools are protected from debris. Another advantage is that the apparatus has a completely open top end for full flow of the fluid into the screen. Yet another advantage is that the embodiments disclose different types of screens, namely a ribbed screen, perforated openings, and/or wire mesh. Still yet another advantage is in the event that the filter is inadvertently left in the tubular string, the design allows for retrieve from the tubular string, with retrieval possible to many thousand of feet below the surface of the earth.
A feature of the present invention includes the screen has cylindrical walls. The screen has an open top end and a base with openings therein. Another feature is the flange that is connected via shear pins to the fishing neck. Yet another feature is use of a disclosed wire line pulling tool to retrieve the apparatus from the tubular string within a well bore. Still yet another feature includes the ability to pull significant forces via the wire line in order to retrieve the novel apparatus.